Although it is not a graphicly impressive game, the hardest thing involved
in creating this game was
to offer great gameplay at an easy difficulty. It is very easy for a player
to lose track in the game.
Even with an included tutorial, we got feedback from beta testers that
finished the test level in 9 minutes, some that did it in more than 30,
or some that didn`t understand what all this was about.

This raises an interesting question in game development: gameplay duration.
As a developer I can finish the game in no time, as I know everything
about it. But how
long does it take for an average player to finish one level?
You can't make a level take too long, as the player will become bored, but
also you can`t keep it too short.
One feature I recomend to you when releasing a demo: Track the time needed for
a player to finish the game.
It can make a huge difference in your game.